# Return from contained subroutine

**URL:** <https://fortran-lang.discourse.group/t/return-from-contained-subroutine/833>\
**Category:** Uncategorized\
**Created:** [March 15, 2021, 1:33am UTC](https://fortran-lang.discourse.group/t/return-from-contained-subroutine/833 "2021-03-15T01:33:16Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Beliavsky](https://avatars.discourse-cdn.com/v4/letter/b/ba8739/32.png) [@Beliavsky](https://fortran-lang.discourse.group/u/Beliavsky)\
**Post date:** [March 15, 2021, 1:33am UTC](https://fortran-lang.discourse.group/t/return-from-contained-subroutine/833/1 "2021-03-15T01:33:16Z")

</div>

If subroutine foo CONTAINs subroutine bar, is there a way to RETURN from (exit) foo from within bar? I would like to handle errors within a CONTAINed subroutine, and if there is an error, to return from foo, not just bar. Schematically, this is the problem:

```
subroutine foo()
call bar(ierr)
contains 
subroutine bar(ierr)
if (ierr /= 0) then
   print*,"in foo, ierr = ",ierr
   return ! RETURNs to foo, not to the caller of foo
   ! allow "return_from foo"?
end if
end subroutine bar
end subroutine foo

```

In other languages, `return foo` means return the value foo, so Fortran should not have the same syntax with a different meaning. Maybe allow syntax such as  
`return_from foo`?

---

<div class="post-metadata">

**Author:** ![FortranFan](https://avatars.discourse-cdn.com/v4/letter/f/96bed5/32.png) [@FortranFan](https://fortran-lang.discourse.group/u/FortranFan)\
**Post date:** [March 15, 2021, 2:54am UTC](https://fortran-lang.discourse.group/t/return-from-contained-subroutine/833/2 "2021-03-15T02:54:56Z")

</div>

> [@Beliavsky](#):
>
> … is there a way to RETURN from (exit) foo from within bar? I would like to handle errors within a CONTAINed subroutine, and if there is an error, to return from foo, not just bar.,

To the best of my knowledge, there isn’t a mechanism in the language to exit the host procedure via a RETURN from a contained procedure. I personally don’t think such an option will be good for Fortran, I would never use it.

One can consider adding a dummy argument to the `foo` toward an error handling callback procedure that foo/bar can invoke which can then allow the caller to take control of the situation.

Or, there is always the `ALTERNATE RETURN`, a poor Fortranner’s substitute due to **relentless** kicking off the “can down the road” by the standard-bearers when it comes to providing any **modern** exception handling facility in the language. This can permit `foo` to complete whatever `cleanup` may be necessary before exiting the subprogram.

```Fortran
module m
contains
   subroutine foo(ierr)
      integer, intent(out) :: ierr
      call bar(ierr,*999)
      return
 999 continue
      print *, "run-time exception in bar: ierr = ", ierr
   contains
      subroutine bar(irc,*)
         integer, intent(inout) :: irc
         real :: x
         call random_number(x)
         ierr = 0
         if ( (x > 0.4).and.(x < 0.6) ) then
            ierr = 1
            return 1
         end if
         return
      end subroutine 
   end subroutine 
end module
   use m, only : foo
   integer :: i, ker
   do i = 1, 100
      call foo(ker)
      if ( ker /= 0 ) stop
      write( *, fmt="(g0,1x)", advance="no") i 
   end do
end

```

> C:\Temp\>ifort /standard-semantics p.f90  
> Intel(R) Fortran Intel(R) 64 Compiler Classic for applications running on Intel(R) 64, Version 2021.1.2 Build 20201208\_000000  
> Copyright (C) 1985-2020 Intel Corporation. All rights reserved.
> 
> Microsoft (R) Incremental Linker Version 14.28.29337.0  
> Copyright (C) Microsoft Corporation. All rights reserved.
> 
> -out:p.exe  
> -subsystem:console  
> p.obj
> 
> C:\Temp\>p.exe  
> 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22  
> run-time exception in bar: ierr = 1
> 
> C:\Temp\>